The class of polymers of carbon monoxide and olefin(s) has been known for some time. Brubaker, U.S. Pat. No. 2,495,286, produced polymers of carbon monoxide, ethylene and optionally, additional olefinic monomers in the presence of free radical catalysts, e.g., peroxy compounds. The polymers had a relatively low carbon monoxide content. G.B. 1,081,014 produced similar polymers of somewhat higher carbon monoxide content in the presence of trialkylphosphine complexes of palladium compounds as catalyst. Nozaki extended the reaction to produce linear alternating polymers in the presence of arylphosphine complexes of palladium moieties and certain inert solvents. See, for example, U.S. Pat. No. 3,694,412.
More recently, the class of linear alternating polymers of carbon monoxide and at least one ethylenically unsaturated hydrocarbon has become of greater interest in part because of the greater availability of the polymers. The more recent processes for the production of the linear alternating polymers, now becoming known as polyketones or polyketone polymers, are illustrated by a number of published European Patent Applications including 121,965, 181,014, 213,671 and 257,663. These processes generally involve a catalyst composition formed from a compound of a Group VIII metal selected from palladium, cobalt or nickel, the anion of a strong non-hydrohalogenic acid and a bidentate ligand of phosphorus, arsenic or antimony. The scope of the polymerization process is extensive but, without wishing to be limited, preferred catalyst compositions are formed from a palladium compound, the anion of a non-hydrohalogenic acid having a pKa below 2 and a bidentate ligand of phosphorus which is typically a tetraaryl diphosphine ligand. The resulting polymers have established utility as premium thermoplastics in the production of shaped articles by methods which are conventional for thermoplastics.
When copolymers of carbon monoxide and ethylene are produced, polymerization leads to a single type of product. Because of the lack of pendant groups in the ethylenically unsaturated hydrocarbon moiety, the geometry of the polymerization does not distinguish between the carbon atoms of the ethylene. When an olefin of three or more carbon atoms is employed in the production of linear alternating copolymers with the carbon monoxide, the geometry of the polymerization could lead to somewhat different products. If the majority of the propylene units combine with the moieties from carbon monoxide in a head-to-tail manner, i.e., a ##STR1## manner, the resulting polymer is termed regio-regular. If the combination is not in a predominantly head-to-tail manner the polymerization is termed regio-irregular. In U.S. Pat. No. 4,970,294, the polymerization of carbon monoxide and propylene is conducted in the presence of a catalyst composition formed from a compound of palladium, an anion of a strong non-hydrohalogenic acid and a tetraaryl phosphine as the bidentate phosphorus ligand. The resulting linear alternating copolymer of carbon monoxide is regio-irregular. The activity of the catalyst composition in the production of such copolymers is, moreover, relatively low as compared to polymerizations of ethylene. It would be of advantage to provide a more active catalyst composition for the production of linear alternating copolymers of carbon monoxide and an ethylenically unsaturated hydrocarbon of at least 3 carbon atoms.